[Bug d/87866] gdc fails to compile minimal test

[ro at CeBiTec dot Uni-Bielefeld.DE]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87866

--- Comment #2 from ro at CeBiTec dot Uni-Bielefeld.DE <ro at CeBiTec dot Uni-Bielefeld.DE> ---
> --- Comment #1 from Iain Buclaw <ibuclaw at gdcproject dot org> ---
> I backported a fix from the D sources so it should no longer segfault at least.

It doesn't indeed.

> From what I can see, it should pick up the object.d source correctly.
>
>     -nostdinc -I /vol/gcc/src/hg/trunk/local/libphobos/libdruntime 
>
> Unless it really isn't in the -I path.

I've found what's going on:

When d-incpath.dd (add_globalpaths) calls into Filename::canonicalName
(path), path is set correctly to the d21 -I arg:

81                const char *target = FileName::canonicalName (path);
(gdb) p path
$7 = 0x9f33878 "/vol/gcc/src/hg/trunk/local/libphobos/libdruntime"

(gdb) s
0x0833cea6 in FileName::canonicalName (
    name=0x9f33878 "/vol/gcc/src/hg/trunk/local/libphobos/libdruntime")
    at /vol/gcc/src/hg/trunk/local/gcc/d/dmd/root/filename.c:616
616         return realpath(name, NULL);
(gdb) n
83                if (target == NULL || !FileName::exists (target))
(gdb) p target
$8 = 0x0

However, canonicalPath returns with NULL.  I traced this to realpath(3C)
on Solaris 10 behaving differently, as explained in the man page:

     bolic  links.  The  generated  pathname is stored as a null-
     terminated string, up  to  a  maximum  of  {PATH_MAX}  bytes
     (defined  in  limits.h(3HEAD)),  in the buffer pointed to by
     resolved_name.

RETURN VALUES
     On successful completion, realpath() returns  a  pointer  to
     the  resolved  name.   Otherwise,  realpath() returns a null
     pointer and sets errno to indicate the error, and  the  con-
     tents  of the buffer pointed to by resolved_name are left in
     an indeterminate state.

Unlike e.g. the Solaris 11.4 version, realpath doesn't allocate a buffer
on it's own if the second arg is NULL, but given that it couldn't store
the real path, returned NULL to indicate that failure.

        Rainer